package com.gitee.candy.encry;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * 前后端传数据加解密工具类
 */

/**
 * 对称加密
 */
public class EncryptAESUtils {

    //使用AES-128-CBC加密模式，key需要为16位,key和iv可以相同！
    // 前后端要一致，前端在 http.js中
    private static String KEY = "0123456789123456";

    private static String IV = "0123456789123456";

    /**
     * 加密方法
     *
     * @param data 要加密的数据
     * @param key  加密key
     * @param iv   加密iv
     * @return 加密的结果
     * @throws Exception
     */
    public static String encrypt(String data, String key, String iv) throws Exception {
        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");//"算法/模式/补码方式"NoPadding PkcsPadding
            int blockSize = cipher.getBlockSize();

            byte[] dataBytes = data.getBytes();
            int plaintextLength = dataBytes.length;
            if (plaintextLength % blockSize != 0) {
                plaintextLength = plaintextLength + (blockSize - (plaintextLength % blockSize));
            }

            byte[] plaintext = new byte[plaintextLength];
            System.arraycopy(dataBytes, 0, plaintext, 0, dataBytes.length);

            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
            byte[] encrypted = cipher.doFinal(plaintext);

            return EncryptBASE64Utils.encode(encrypted);

        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 解密方法
     *
     * @param data 要解密的数据
     * @param key  解密key
     * @param iv   解密iv
     * @return 解密的结果
     * @throws Exception
     */
    public static String decrypt(String data, String key, String iv) throws Exception {
        try {
            byte[] encrypted1 = EncryptBASE64Utils.decode(data);

            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

            byte[] original = cipher.doFinal(encrypted1);
            String originalString = new String(original);
            return originalString.trim();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 使用默认的key和iv加密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public static String encrypt(String data) throws Exception {
        return encrypt(data, KEY, IV);
    }

    /**
     * 使用默认的key和iv解密
     *
     * @param data
     * @return
     * @throws Exception
     */
    public static String decrypt(String data) throws Exception {
        return decrypt(data, KEY, IV);
    }

    /**
     * 测试
     */
    public static void main(String args[]) throws Exception {
        String test1 = "宝剑分从磨砺出，梅花香自苦寒来";

        String data = encrypt(test1);
        System.out.println("加密：" + data);
        String jiemi = decrypt(data);
        System.out.println("解密：" + jiemi);
    }

}
